Rios et al1 identified a statistically significant association between the HLA-Cw4 allele and multinodular goiters (15.5% vs 8.3%; P = .001; relative risk = 0.49). This finding was based on a comparison of 90 surgical patients with multinodular goiters from a single institution with a control group of 100 unrelated, healthy blood donors “representative of the healthy population.”